US Patent 7852499 Captions detector

To detect captions in a document that includes text fragments and objects of interest, a signature is assigned to each text fragment. The signature is the value for that text fragment of a text fragment representation comprising at least one text fragment attribute. A caption signature is identified as a signature assigned to a substantial number of text fragments that are near at least one object of interest in the document. One or more captions are detected as one or more text fragments each assigned a caption signature.